Plant of the Day: Sensitive Plant

Are you ready to read all about a brand-new Awesome Plant of Awesomeness? I hope so, because I feel like doing another round of Plant of the Day. And so it was.

At first glance, the Sensitive Plant seems nondescript, but it is actually a bit of a marvel of nature — and cute, to boot. When it feels menaced, whether by touch, heat, or shaking, its leaves fold inward and it droops surreptitiously downward. Observe:

Who: Sensitive Plant / Mimosa pudica
(Family: Pea Family / Fabaceae)

What: The sensitive plant is an herb that grows to be about 50-70 centimeters tall, sometimes taking the form of a spiky sub-shrub and sometimes creepin’ prostrate along the ground. It can be either annual or perennial because it just does what it wants. It is often considered a weed, unfortunately, so it’s probably not wise to plant your entire lawn full of them. Here are some of its characteristics:

  • lilac-pink “pompom” flowers, which are actually a flower head of 1-5 flowers clumped together
  • a flower color/appearance that comes almost entirely from its stamens’ filaments; its corolla (all the petals) and its calyx (all the sepals) are tucked away discreetly, as with many Mimosoideae, doncha know
  • stems that are often covered in prickles or bristles
  • bipinnately compound leaves, aw yeaaah! In this case, that means that a single leaf is divided into 1-2 pinnae, which in turn are subdivided into 10-26 pairs of thin, long, touch-sensitive leaflets
  • prickly brown pods, clustered together

For those of you who are fourteen years old, I present this partial description from Wikipedia: “The stem is erect in young plants, but becomes creeping or trailing with age. It can hang very low and become floppy.”

Its sensitivity to touch and other stimuli is called seismonasty. This may be a defense against herbivores, who might be startled by its rapid movements. It also exhibits nyctinasty, which is a plant’s subtler circadian movement which is controlled by the onset of dusk/night (e.g. petals closing, leaves folding up).

By Eric Hunt (Own work) [GFDL or CC-BY-SA-3.0-2.5-2.0-1.0], via Wikimedia Commons
Fluffy! (By Eric Hunt (Own work) [GFDL or CC-BY-SA-3.0-2.5-2.0-1.0], via Wikimedia Commons)
I can’t resist etymology, so: its genus name Mimosa comes from the Greek word mimos (“mimic”), alluding to the way it moves in reaction to outside movement. Meanwhile, its species name pudica comes from a Latin word meaning “bashful or shrinking to contact.” Shy little mimic.

In addition to its scientific name and the common name I used above, it also has a wealth of excellent common names in other languages, including:

  • moriviví / “I died, I lived” (in Spanish / the Dominican Republic and other Caribbean countries)
  • mateloi / “false death” (in Tongan / Tonga)
  • putri malu / “shy princess” (in Indonesian / Indonesia)
  • muttidare muni / “angered by touch” (in Kannada / India)
  • hti ka yoan / “crumbles when touched” (in Burmese / Myanmar)

(All of these are grabbed from the ever-reputable Wikipedia, so if they’re at all inaccurate, blame my weakness for interesting, probable-sounding common names.)

Where: Sensitive plants are originally from tropical areas in Central and South America. However, they have spread around the world, especially in disturbed tropical areas, and they are regarded as invasive by quite a few countries and regions (including Tanzania, Australia, South Asia, and elsewhere). Spay and neuter your sensitive plants, folks.

Why: Despite their nasty invasive tendencies, they have elegant, delicate little leaflets and appealing pompom flowers… but honestly, it’s all because of how bloody cool this is:

It just has a lot of feelings, okay! (By Hrushikesh (Own work) [CC0], via Wikimedia Commons)
One more — look at that sexy seismonasty in action!:

By Tauʻolunga (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons
By Tauʻolunga (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

* JSTOR: Entry for Mimosa pudica
* Kew Royal Botanical Gardens: Mimosa pudica
* Wikipedia: Mimosa pudica

2 thoughts on “Plant of the Day: Sensitive Plant

  1. Hello, muttidare muni, daughter o’ mine.

    You have picked a fine species to write about. I LOVED mimosas when I was little. Their leaves were my main prop when playing Mailman. Mailman was a game I invented in which I would laboriously separate each leaflet from the master frond. I’d gather these in the palm of my hand where they became letters that I had to deliver to various stick and acorn people. Surely you understand the logic and allure of this complex game.

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